Hot-air syringe.



O. H. & A. F. PIEPER.

l HLoT MR SYRINGE. APPLICATION FILED OCT. 4. i915. RENEWED APR. 24,lgl..

Patented 3fm. 8, 1918.-

37 23 `l7 7' n Y UNITED STATES PATENT OFFICE.

OSCAR H. PIEPEB AND ALPHONSE F. PIEPER, OF ROCHESTER, NEW YORK.

HOT-AIR SYRINGE.

Specication of Letters Patent.

Patented Jan. 8, 1918.

Application led October 4, 1915, Serial No. 53,951. Renewed April 24,1917. Serial No. 164,280.

To all whom it may lfonc-ern:

Be it known that we, OSCAR H. Prisma and ALPHONSE F. Purnn, both ofRochester, in the county of Monroe and State of New York, have inventedcertain new and useful Improvements in Hot-Air Syringes; and we dohereby declaring the following to be a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming a part of this specification and to thereference-numerals marked thereon.

Our invention has for its purpose to improve the construction of hot airsyringes of the type that is employed in dental work, and embodyinggenerally a valve controlled supply of fluid under pressure, and anelectrical heating unit for warming the air before it reaches thedischarge point of the instrument, and more particularly the improvementconsists in novel and readily controlled devices, whereby the heatingunit is rendered effective when the Huid valve is opened, and viceversa. Further, the invention contemplates the provision of means forheating the air more thoroughly by subjecting it to a maximum effectfrom the heating unit.

Arranged in the casing 1 is a removable heating unit, or element, whichpreferably consists of inner and outer tubular` walls 12 and 13 fastenedtogether in spacedrelation, the outer tube being closed at one end.while the inner tube is opened at both ends, and, in the presentinstance, is connected to the outer tube at the open end of the latterby a wall, or ilate, 1G. This plate is preferably connecte to the outertube by expanding the open end of the latter slightly to receive theplate and then forming the projecting end of the tube over the plate.The enlargement 16 thus produced at the outer end of the tube 13 engagesa tube 15 secured at its inner end to an insulating member 18, which isseated within the intermediate section, or head, 3, and held therein byengagement with the inner end of the threaded casing 1. A heating coil11 surrounds the inner tube 12, one end of the coil being connected tothe plate 16 and the other end to an attaching member, or screw, 14,which passes through the closed end of the outer tube and is insulatedtherefrom by washer 14* and secured by a nut 14. K

The heating element, or unit, is held firmly in place with the enlargedend 16 in engagement with the outer end of the tube 15 by means of thescrew 14, which engages within a threaded securing member 18 carrled bythe insulating member 18. The tubes 13 and 15 are spaced from each otherexcept where they contact at their outer ends,'and the tube 13 isprovided with perforations 17 adjacent the enlargement 16 in order thatair admitted within the tube 15 may pass around the outer tube of theheatlng element, and after entering the perforations, pass between theinner and outer tube thence within the inner tube to the outer` en ofthe casing 1, escaping by a nozzle 2.6.

This nozzle is held within the cap 27 by means of a spring Q8 engagingthe base of the nozzle and retained in position by a threaded sleeve 29.An asbestos sleeve 30 is provided inside the casing 1 and adjacentthereto, in order to prevent the latter from becoming unduly heated fromthe heat that is generated by the coil 11.

It will be observed that., with current flowing in the heating coil, airadmitted within the chamber 15 is subjected to a lcertain amount of heatradiating from the coil through the outer tube 13, while passing betweenthe two tubes. After passing through the openings 17 the air comes indirect contact with the resistance coil until it reaches the inner endof the tube 1:2. Again, in passing within the latter tube the air issubjected to the heat radiating from the coil through said tube. y

The instrument is adapted to be connected to an air pipe 39 leading to asource of compressed alr, and to this end the handle 2 is provided withan air pipe attaching sleeve 23, internally threaded to receive thecoupling member 2l on the end of the pipe. The member 21 carries aportion 41 adapted to seat against a tubular portion 4 carried by thesleeve 23, to make an air tight joint, and the air passage in theportion 4 communicates with a passage 38 in the head 3, leading to thevalve chamber 5.

Upon opening the valve 6 air is allowed to flow through the air pipe 39and tubular portion 4, past the valve, into a passage 31 in the head 3,and into a chamber 32 beneath the insulating member 18. A passage 33 inthe latter communicates with the interior of the tube 15, so that theair admitted by the valve can enter said tube and be subjected to theaction of the heating coil In order to' enable the circuit througlrthecoil 11 to be closed when the air is admitted,

We provide a switch arm 29, which is'actuated by a A plunger"25arrangedr beneath the valve thumb piece 8, and is adapted to engagewith an insulated contact plate 2'1connected by a wire 2O passingthrough a channel 'i'n -the head -'leading to the chamber 32 and throughan aperture inthe insulating bloclclS to the tube 15. The switch arm 22,which thus makes electr-ical contact through the'tubes 15 and 13. to theplate/1G- structure located at one side of theV head 3,V

and the upper of the tubularl portion l is offset to communicate withthe passage 3S,

leading to the valvechamber. The tubular portion is insulated. from the1head by a sleeve 3G-tightly surrounding the tube and fitting within arecess in the head to make. an air tight joint, An aperture 37 at thebase of the sleeve allows the passageot .air

from' the tube to the passage 3,8.

'l`he member .4 connected by a yWine 1,5),` leading through a channelinthe head into the chamber 3.2 anda'ttached -tothe sleeve 18, whichlatter. makeselectifieal connection through the screw 14 to the'inner.end oii the heating coil.. Connection is made to an elec-4 triccircuitby wires A and which .lead within the fair ,pipe 39, and are connectedrespectively to the outerand inner contact sleeves =l0 and Lllun'hichareinsulated from each other, the former engaging the termif nal sleeve23, while thelatter makes contact; with the tubular member 4, whichconsti,- tutes the other 'terminal ofthe. instrument circuit,l i Itwillbe observ-cdithat this. const ructien affords a convenientineans Where:by the electrical and airfeonnections of the illSfr-ilmeiitflirly *befmede "multveuslylvhenthe tlliumb. piece ,8 ofthe, xyalve is `de;`lpressed-.the current passes from-,conductor A. tocontact, sleeve23,-switch arm 22, Contact plate 21,--wire 20, tube 15, heating coil 11, sc rewllfgsleeve- 1S, ufire 1Q., tubular member ft, sleeve tf1 rind.conductor Att the same tilneair is admitted from thepipe 39 through thecentral passages in the con tact sleeves 4Q and all through member 4. topassage- 38, valve chamber 5,1m] as before describedpast thelieatingfcoilescaping by the nozzle 2G.

The structure which -hasfbeen :described is an exceedingly efficient-onein dental worl, ahd'can; be manufactured at a cost` that. is" Veryreiuionable,4 besides. atfoizdi'g an which is admirablyfala'pted forthetine, delicate class of instruments that are ein- '.lVe claim as ourinvention 1. In a hot air syringe, the combination Wlth a` heating coiland an electric c1rcu1t ycontrolling it, of an inner tube Within saidcoil; and aiioutertube surrounding itclsed at oneend ,a-ndconnected atits opposite end with the inner tube by a Wall, the outer tube havingopenings adjacent the last mentioned W- all Wherebythe incoming airiscaused :to pass around the outside of the outer tube, thence interiorlythereof in engagement with the heating coil, and thence withinrtheinner4 tube and-,lengthwise thereof.

2. In ahot air syringe, the combination with ahead having a recess and'provided With an integral portion forming a handle having an air passagetherein communicating with the recess, and a `Valve vcontrolli-ng theflow of air therein, of a tubular airconducting lportion fitted intherecess, an electric heatingelement in said air conducting portionandcircuit conductors for said heating element. inclosed within the handleand head.

3. In' a hot air syringe, the combination Witha head, ,a nozzle portionon the head, a heating element located therein, .and a. handle-portioncarrying the head having an air passagetherein and provided with athreadedV attaching portion concentric ivith said. passage, of a pipeconnection coperating with said threaded `portion and comprising a. part.adapted ,to form a tight joint with the end of the air-passage.

, 4. In a hotair syringe, the combination With a head, a nozzle portionthereon,an electric heating element located in said noz,- Zle por-tionand a metallic handle portion carrying'.4 the head provided with an airpassage, of a threaded metal sleeve concentric to. the air passageandinsulated from thehandle portion, a metal air pipe connection havingthreaded engagement with said sleeve and provided with an insulatedmetal tube fitting against the end of. the air pasf sage, saidconnection and its tube forming the two, sides of an electriccircuit,and circuit connections between the parts of .the handle and the heatingelement.

5. In a hot air syringe, the combination With ay body portion having anair passage therein and a valve for controlling the How ot airtherethrough, of a heating coil, a slee-ve insulated from the bodyportion and forming one termi-nal of the coil, a tubular member carriedby and insulated from the sleeve forming the other terminal. and aninsulation interposed between the body por.- tion and tubularmember, thepassage inthe tubular member communicating with vthe passage` in' thebody portionthroughan aperture in thes-usldating member.

6. In a hot air syringe, the combination with a body portion having anair assage therein and a Valve for controlling t e flow of airtherethrough, of a heating coil, an air supply pipe attaching sleeveinsulated from the body and forming one terminal of the coil, a tubularmember carried by the sleeve and insulated therefrom and from the bodyportion constituting the other terminal, the passage in the tubularmember communicating with that in the body, and an air supply pipeconnection having outer and inner sleeves insulated from each other andcontacting respectively with the attaching sleeve and tubular portion,the two sleeves being adapted to be connected to the terminals of anelectric circuit.

7. In a hot air syringe, the combination with a heatin g elementembodying outer and inner walls forming air passages and a heating coilin one of the air passages, of a tube surrrounding the heating elementandengagin the outer end of the latter but spaced there rom theremainder of its length, the outer wall of the heating element having anopening adjacent its outer end whereby air passing between the tube andheating element 1s admitted to the air passagesand heating coil.

8. In a hot air syringe, the combination with a heating elementembodying outer and inner walls forming air passages and al heating coilin one of the air passages, of a tube surrounding the heating element inspaced relation, an enlargement at the outer end of the heating elementengaging the end of the tube to make an air tight joint, and means forholding the heating element and tube in engagement, the outer wall ofthe heating element having an opening adjacent the enlargement wherebyair passing between the tube and heating element is admitted to the airpassages and heating coil.

9. In a hot air syringe, the combination with a tube and an insulatedsecuring portion at one end thereof, each adapted to be connected toterminals of an electric circuit, of a removable heating element withintube in contact therewith, having an insulated attaching portioncoperating with the insulated securing portion, and a heating coilwithin the heating element in electrical contact therewith and with theattaching portion, and means for controlling the admission ofair throughthe heating element and past the heating coil.

10. In a hot air syringe, the combination with a body having an airpassage therein and a valve for controlling the flow of airtherethrouvh, of an air pipe attaching sleeve insulated rom the bodyportion, a tubular portion carried by the sleeve and insulated therefromand from the body portion having an air passage therethroughcommunieating with the air passage in the body portion, the sleeve andtubular portion constituting contact members adapted to be connected tothe terminals of an electric circuit, a tube carried by the bodyportion, an insulated securing portion at one end thereof, electricalconductors connecting the two last named members with the contactmembers, a removable heating element within the tube in contacttherewith, having an insulated attaching portion cooperating with theinsulated securing portion, a thermo coil within the heating elementconnected at one end thereto and at the other with the attachingportion, and a switch in one of the conductors controlled by the valve.

11. In a hot air syringe, the combination with a body portion having anair passage therein and a valve for controlling the flow of airtherethrough, of a heating coil, a. sleeve insulated from the bodyportion, a tubular portion carried by the sleeve and insulated therefromand from the body portion, having an air passage therethroughcommunicating with the air passage in the body portion, the sleeve andtubular portion constituting contact members adapted to be connected tothe terminals of an electric circuit, an insulated switch member on thebody portion, conductors leading from the opposite ends of the coil tosaid switch member and one of the contact members respectively, and acoperating switch member on the other contact member, one of the switchmembers being controlled by the valve and adapted to make contact withthe other when the valve is opened.

OSCAR H. PIEIER. ALPHONSE F. PIEPER. Witnesses:

R. M. "WRIGHT, F. I. lVILsoN, V. R. HUMPHnEYs, J. H. KLINE.

'opies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

